FRET between NV centers in diamond and chlorophyll molecules: a novel resource for multimodal sensing and imaging in plant cells

TL;DR

This study demonstrates efficient FRET between shallow NV centers in diamond and chlorophyll molecules, enabling combined optical sensing and magnetic resonance techniques for potential applications in plant cell imaging.

Contribution

It introduces a novel FRET system between NV centers and chlorophyll, showing potential for multimodal sensing and imaging in biological environments.

Findings

FRET reduces NV fluorescence lifetime from ~14 ns to below 4 ns

FRET efficiency depends on proximity of NV centers to chlorophyll

NV spin properties are preserved during FRET-based sensing

Abstract

This work demonstrates efficient Forster resonance energy transfer (FRET) between ensembles of shallow nitrogen-vacancy (NV) centers located 7 nm and 9 nm below a single-crystal diamond surface and a naturally occurring fluorophore, namely a mixture of chlorophyll a and b molecules extracted from Arabidopsis thaliana. The broad fluorescence band of NV centers spectrally overlaps with the absorption of chlorophyll molecules, enabling FRET. As a result, depositing a chlorophyll layer on the diamond surface reduces the NV fluorescence lifetime from approximately 14 ns to below 4 ns, indicating efficient energy transfer. Laser-induced photobleaching of chlorophyll restores the unquenched NV lifetime. In contrast, NV centers located deeper within the diamond at depths of 40 nm and 72 nm remain unaffected, confirming that the observed quenching originates from a short-range FRET mechanism. The NV ensembles retain their optically detected magnetic resonance contrast while FRET is observed, demonstrating preservation of their spin properties. These proof-of-principle experiments establish the feasibility of combining FRET-based distance measurements with magnetic sensing using optically readable spins.